In Europe, there has been a serious decline in physical activity over the past 50 years. Adults aged 20-60 years(1)_____ 500kcal less energy per day than they did 50 years ago. This is the(2)_____ to the running of a marathon each week. Even(3)_____ of participation in walking and cycling are declining. All of which suggests we should be(4)_____ to the nearest gym. But the "green" policies of these establishments(5)_____ to be pretty disappointing: factor in air-conditioning, laundering of towels, energy-consuming exercise(6)_____ and the fact that 90% of exercisers(7)_____ to the gym. British Military Fitness, the UKs leading (8)_____ fitness provider, offers a programme of nationwide classes in parks, and on common lands, in the(9)_____ of its Gym Intervention programme. The organisation advocates not just the fitness benefits of working out outside,(10)_____ our need to spend time in the great outdoors to(11)_____ overall mental and physical wellbeing. Group activity is declining as fast as our fitness rates, so the complete moral workout doesnt merely(12)_____ the greenness of the equipment, but also the social capital to be(13)_____ by joining in. It also(14)_____ to start early. Children urgently need to become more(15)______, and yet according to Natural England, a public body that encourages people to enjoy their natural surroundings, the amount of time and(16)_____ children have with nature is declining; fewer than 10% now play in natural places(17)_____ woodlands, countryside and common land compared with 40% of children 40 years ago. Research shows that children who are(18)_____ to nature will continue to visit (19)_____ landscapes in adulthood and be committed(20)_____ retaining them.
(1)

A. exit
B. exhaust
C. execute
D. expend